Merge pull request #1800 from joshmoore/1387-simple-salt

Simple salting of MD5 passwords (See #1387)
Merge pull request #1842 from mtbc/db-version-beta2

upgrade database version to beta2
Merge pull request #1845 from joshmoore/rebased/develop/disable-chgrp-event-logs

Disable chgrp event logs (rebased onto develop)
Merge pull request #1853 from joshmoore/rebased/develop/11709-tile-access

11709 tile access (rebased onto develop)
Merge pull request #1861 from mtbc/trac-11693-rename-current-group

fix #11693: prevent rename of user's current group
Merge pull request #1866 from bpindelski/11154-logfile

Make log filename setting secure (see #11154).
Fail properly on import failure
Minor cleanup
Enable memoization for all server-side OMEROWrapper uses
Fix check if not empty
merge develop -D org -I include -E exclude: PR 1385 (Update the OMERO VirtualBox image)
merge develop -D org -I include -E exclude: PR 1712 (Create release source artifact containing all submodules)
merge develop -D org -I include -E exclude: PR 1779 (Copy rendering 11552)
merge develop -D org -I include -E exclude: PR 1807 (Cleanup TableI.close() #11697)
merge develop -D org -I include -E exclude: PR 1811 (11607 scripts)
merge develop -D org -I include -E exclude: PR 1818 (Error handling of tile image loading in PanoJS See #11709)
merge develop -D org -I include -E exclude: PR 1838 (Connection)
merge develop -D org -I include -E exclude: PR 1840 (Webstart popup windows 11656 develop)
merge develop -D org -I include -E exclude: PR 1849 (Extract Django when it's missing or is the wrong version)
merge develop -D org -I include -E exclude: PR 1863 (Use python's json rather than Django's)